ODATEL

Testing LTE, and VoLTE

Testing LTE, and VoLTE

Overview

Long Term Evolution (LTE) is the so called 4th Generation (4G) mobile standard in the rapidly evolving mobile technologies. Its distinguishing feature is an all IP infrastructure and significantly greater air interface bandwidth to the mobile handset. It was developed as an enhancement to the existing 3G UMTS System (Universal Mobile Telecommunications System) to provide users enhanced mobile radio and internet access.

The LTE air interface is a completely new system based on orthogonal frequency-division multiple access (OFDMA) in the downlink and single-carrier frequency-division multiple access (SC-FDMA) in the uplink. The system efficiently supports multi-antenna technologies (MIMO).

Another significant feature of LTE is its high bandwidth—up to 20 MHz. The LTE can also operate in the existing 5-MHz UMTS frequency bands, or in even smaller bands, as the usable bandwidth is scalable.

However, deploying high-quality voice, video, and data services over LTE has posed significant challenges for service providers, due to backward-compatibility, inter-operability, and high quality requirements – all of which requires rigorous testing.

GL’s LTE Test Solutions

GL’s provides fully automated testing solutions for LTE, VoLTE, and IMS network as discussed in greater detail below.

The representation of LTE–IMS network above indicates the support of most of the interfaces by GL’s test tools. In summary, End-to-end voice, video, and data quality testing with speech metrics such as PESQ, and POLQA. This solution combined with other metrics such as delay, packet loss, drops, and more, the true performance of VoLTE can be realized.

All elements within LTE-IMS wireless infrastructure can be tested with GL’s general-purpose protocol simulation tool – MAPS™, which supports simulation of various interfaces of LTE (S1-u, S1-MME, X2, S3, S4, S5/S8, S6a, S10, S11, S13, S16) and IMS (Cx/Dx, Rx, Gx, Gm, SGi, Mw, Mi, Mj) interfaces using MAPS™ LTE, Diameter, and IMS simulators. With these, one can simulate VoLTE calls in lab, and study the network behaviour.

GL’s PacketScan™ – an All-IP monitoring and analysis probe, along with NetSurveyorWeb™ allow centralized monitoring of entire LTE-IMS network. Wide range of codec support, including AMR WB, and extensive per-call reports

Monitoring LTE-IMS (VoLTE) Networks

GL’s PacketScan™ – an All-IP Network Monitoring software offers powerful features to capture and monitor live signaling and traffic over IP. PacketScan™ with Voice, Data, and Video QoS capability addresses customers long felt need of call quality analysis in IP networks.
Capable of capture, decode and perform various test measurements between any two nodes across various interfaces of the LTE-IMS network
Support for wide-range of codec, including AMR and AMR WB – visit Voice Codec webpage for more details.
Supports QoS parameters such as E-model (G.107) based MOS/R-Factor scores, Media Delivery Index (Delay Factor: Media Loss Rate) for video calls, Jitter, Delay, and Gap for Audio and Video traffic
Segregates, captures, and collects statistics on VoIP and Wireless calls
Live monitoring of traffic statistics – digits, tones, voice, video, and T.38 fax over IPv4 and IPv6 (version 4 and version 6) networks
Monitors QoS (quality of service) on voice and video calls
Supports both real-time and offline analysis
Trace files for analysis can be loaded through simple command-line arguments.
As an example, the screenshot below illustrates how VoLTE call is easily decoded in GL’s Packetscan™ All-IP analyser

Visit PacketScan™ for Wireless Networks or LTE Analyzer webpage for more details. For centralized web-based monitoring LTE Network, visit NetSurveyorWeb™ page.

Signalling and Traffic Simulation over LTE – IMS

MAPS™ SIP IMS test suite is capable of simulating multiple UEs and IMS core elements such as P-CSCF, I-CSCF, S-CSCF, PCRF, MGCF which provides the IMS core network. With the help of mobile phones, and other simulated wireless networks, the VoLTE Lab setup can be operated in real-time for making VoLTE calls and also for interworking with PSTN and VoIP networks. It includes ready-to-use scripts, as per IETF specification. Test scripts include general messaging and call flow scenarios for multimedia call session setup and control over IP networks.

GL’s “MAPS™ 4G Wireless Lab Suite” supports simulation of S1-MME, S11, S5/S8, and other eGTP interfaces along with Diameter interfaces.

  • Supports emulation of several LTE interfaces. (S1, X2-AP, S3, S4, S5, S8, S10, S11 and S16), and IMS interfaces (Cx/Dx, Rx, Gx, Gm, SGi, Mw, Mi, Mj)Supports generation and verification of traffic over LTE, including VoLTE (Voice), Email, FTP, Web (HTTP), Video, and more with additional licenses – Mobile traffic core – GTP (ETH101) and Mobile Traffic Core – Gateway (ETH102)
  • Supports IMS-based technologies such as VoLTE
  • Simulate up to 500 Smartphones (UEs) powering up and down
  • Integrate IMS core network easily with any other networks (wired or wireless) to test any call scenario It can simulate various nodes across LTE network –
  • S1-MME interface – eNodeB (also called Evolved NodeB), and MME (Mobility Management Entity) nodes in
  • eGTP-c interfaces – MME (Mobility Management Entity), SGSN (Serving GPRS Support Node), SGW (Serving Gateway), and PGW (Packet Data Network Gateway)
  • X2-AP interface – two eNodeB (also called Evolved NodeB) end-points
  • Diameter interfaces – MME (Mobility Management Entity), HSS (Home Subscriber Server), AF (Application Function), PCRF (Policy and Charging Rules Function), CSCF (Call Session Control Function), SGSN (Serving GPRS Support Node), PCEF (Policy and Charging Enforcement Function), EIR (Equipment Identity Register) and PDN GW (Packet Data Network Gateway)
  • Authenticate and confirm security procedures
  • QoS requests for greater or lesser bandwidth
  • Temporary addressing management for mobility and security